Geological mapping using GPR and differential GPS positioning: a case study

To ease geological investigations with GPR (Ground Penetrating Radar) in rough terrain, the GPR equipment can be combined with a carrier-phase DGPS (Differential GPS). As traditional communication with GPS (with e.g., the NMEA protocol) involves an inherent time delay, a new method has been constructed to synchronize the measuring with GPS and GPR units in which the GPS is transmitting a trig signal to the GPR. The results of this case study clearly shows that combining GPR- and DGPS-measurements gives an investigation without need of initial land surveying or clearing of obstacles and vegetation. The investigation also gives information of the topography, which allows for a volume estimation of the investigated target, in this case a limestone layer.